To add to the PA madness that is going on here at the moment, I decided today to build one of the 2 QRP Labs 10w PA’s kits i have here. At the risk of inflaming all the QRP Labs fan boys out there, i both love and hate their kits.
I love that they are well thought out, designed and tested and bring a level of professionalism to the whole kit process, but, and this is the clincher for me, they are mostly a total pain in the arse to build and fix when something goes wrong because they are so densely packed.
Now, some of this has a lot to do with my own personal situation, I have arthritis in my fingers and only have about 75% use of some of my fingers and these boards are backed dense. Might be ok if you are perfect dexterity in your hands, but if not, well the build is not impossible, just frustrating. It would be nice to have say 30% more board space on all their kits. It would really make things much easier to work on, for me at least.
Anyway, it works, with 12v, 250ma bias and 15dbm drive I am seeing about 5W out, not 10. To get 10W out i need to drive it into hard clip with 1W input and turn the output into a square wave. Obviously not good. I figure it could probably do with some more bias current. Gain is pretty flat which is a nice thing. I will have to come back to this and play further at some point.
What i might end up doing is copying the design and laying out my own board and having some boards made up using larger ferrites, even if I lose some gain at 28mhz, it would be worth it to me as I dont use 10m anyway. If i do this, i will not be releasing my gerbers, because you know that someone will take them and start selling boards and that would not be good.
